title: A rice cis-natural antisense RNA acts as a translational enhancer for its cognate mRNA and contributes to phosphate homeostasis and plant fitness.
abstract: cis-natural antisense transcripts (cis-NATs) are widespread in plants and are often associated with downregulation of their associated sense genes. We found that a cis-NAT positively regulates the level of a protein critical for phosphate homeostasis in rice (Oryza sativa). PHOSPHATE1;2 (PHO1;2), a gene involved in phosphate loading into the xylem in rice, and its associated cis-NATPHO1;2 are both controlled by promoters active in the vascular cylinder of roots and leaves. While the PHO1;2 promoter is unresponsive to the plant phosphate status, the cis-NATPHO1;2 promoter is strongly upregulated under phosphate deficiency. Expression of both cis-NATPHO1;2 and the PHO1;2 protein increased in phosphate-deficient plants, while the PHO1;2 mRNA level remained stable. Downregulation of cis-NATPHO1;2 expression by RNA interference resulted in a decrease in PHO1;2 protein, impaired the transfer of phosphate from root to shoot, and decreased seed yield. Constitutive overexpression of NATPHO1;2 in trans led to a strong increase of PHO1;2, even under phosphate-sufficient conditions. Under all conditions, no changes occurred in the level of expression, sequence, or nuclear export of PHO1;2 mRNA. However, expression of cis-NATPHO1;2 was associated with a shift of both PHO1;2 and cis-NATPHO1;2 toward the polysomes. These findings reveal an unexpected role for cis-NATPHO1;2 in promoting PHO1;2 translation and affecting phosphate homeostasis and plant fitness.
authors.affiliation: Department of Plant Molecular Biology, University of Lausane, Lausane CH-1015, Switzerland.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Jabnoune
authors.forename: David
authors.initials: D
authors.lastname: Secco
authors.forename: Cécile
authors.initials: C
authors.lastname: Lecampion
authors.forename: Christophe
authors.initials: C
authors.lastname: Robaglia
authors.forename: Qingyao
authors.initials: Q
authors.lastname: Shu
authors.forename: Yves
authors.initials: Y
authors.lastname: Poirier
mesh_terms: D004742:Enhancer Elements, Genetic; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D016372:RNA, Antisense / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D052584:Xylem / Q000378:metabolism
chemical_list: D010710:Phosphates; D016372:RNA, Antisense; D012333:RNA, Messenger; D018749:RNA, Plant